Method and apparatus for loosening fibers of waste paper



J. PAV ETAL July 1l, 1967 METHOD AND APPARATUS FOR LOOSENING FIBERS 0F WASTE PAPER Filed Oct. 1, 1964 3 Sheets-Sheet l July l1, i967 J. PAV ETAL, 3,330,437

METHOD AND APPARATUS FOR LOOSENING FIBERS OF WASTE PAPER Filed Oct. l, 1964 3 Sheets-$heet 2 um! Il", 24ml llllhim. 22

J. PAV ETAL July yl1, 1967 METHOD AND APPARATUS FOR LOOSENING FIBERS OF WASTE PAPER Filed Oct. l, 1964 v 75 Sheets-Sheet 3 INVENTORJ` ATTORN EY United States Patent O 3,330,487 METHOD AND APPARATUS FOR LOGSENING FIBERS F WASTE PAPER Jarmil Pav, 34 Nad Mazankou, Prague 8, Czechoslovakia;

Vaclav Hnetkovsky, Sudomerska, Prague 3, Czechoslovakia; Karel Drda, 9 Za Poricskou branou, Prague 8, Czechoslovakia; and Zbynelr Libnar, 48 U trati, Prague 10, Czechosllovalria Filed Oct. 1, 1964, Ser. No. 400,870 Claims priority, application Czechoslovakia, Get. 4, 1963, PV 5,441/ 63 12 Claims. (Cl. 241-5) The present invention relates to a method and apparatus for loosening fibers of Waste paper.

Waste paper is an important source of raw material for paper and cardboard manufacture. The reuse of waste paper is dependent on its perfect pulping and complete separat-ion of the individual fi-bers which are glued together during the original manufacturing process and the perfect Washing of the fibers.

According to the prior art, waste paper, when used as a source of raw material for paper and cardboard manufacture, are first proces-sed either in slushing apparatus (hydrapulpers, beaters, or the like) or in substantially dry state, after previous steaming, in pulping devices consisting substantially of milling devices of the paper manufacture such as cone mills or the like.

One drawback of the various methods used according to the prior art is that the pulping apparatus used exerts a .too strong mechanical effect upon the paper form-ing fibers so that the latter are broken and shortened under formation of undesirable short fragments. This will not only detrimentally affect the quality of the fibers, but the further processing of the same is made extremely difficult due to the longer dewatering time, low initial strength in wet state and formation of slime and mold during the further processing, which will make the further processing extremely difficult and which will slow ldown considerably further processing.

Furthermore, experience has shown that in heretofore used pulping processes in which t-he fibers are broken and shortened to an undesired extent there will still remain in the paper stocks, thus pulped, fiber agglo-merates and unpulped particles in which the individual fibers are not properly separated so that they cannot be properly washed and cleaned land so that they will stick together with unpulped impurities and inorganic components, such as coloring matter or the like, which in turn will lead to an unsatisfactory end product manufactured from thus processed Waste paper.

It is one object of the present invention to overcome these drawbacks in the manufacture of paper or cardboard from waste paper.

It is a further object of t-he present invention to provide a method and apparatus of efficiently losening fibers of waste paper without unduly breaking and shortening the fibers so that the fibers may subsequently be processed into paper or cardboard of high quality.

It is an additional object of the present invention to provide for an apparatus of loosening fibers of waste paper, which apparatus is made of relatively few and rugged parts so that the apparatus can be operated efiiciently and trouble-free during an extended period.

With these objects in view, the method of the present invention for loosening fibers of waste paper basically comprises the steps of mixing waste paper and water and subjecting the mixture to a coarse pulping operation, thickening the pulp thus obtained, feeding the thickened pulp into a storage tank and subjecting it therein to swelling and hydration, discharging the pulp from the tank while diluting it to a smaller density, and subjecting the diluted pulp to mechanical oscillations at high frequency SSS' Patented July 11, 1967 for loosening the fibers, and finally screening the thus finely pulped stock. Preferably, the pulp is maintained in the storage tank at a density of 10-22%, that is, 10-22% solids in 100% pulp, and diluted while being discharged therefrom to a density of 0.5 to 5%. The thus diluted pulp is fed under considerable pressure in a concentrated stream, which stream is subjected to mechanical oscillations at a frequency of 1.5 to 45K c.p.s.

The apparatus of the present invention for loosening the fibers of waste paper after the same has been subjected to swelling and hydration and after the stock has been diluted to the above-mentioned density, mainly comprises chamber means, nozzle means having an outlet end communicating with the interior of t-he chamber means for directing a pressurized stream of pulp into the chamber means, and vibrator means axially aligned with the nozzle means adjacent said outlet end and vibrating at high frequency for subjecting the stream to mechanical vibrations.

The vibrator means preferably includes a vibrator body axially aligned with the outlet end of the nozzle means and having a tapered substantially -conical end facing the outlet end of the nozzle means. The conical end of the vibrator body has preferably a vertex angle of 60-120 and the point of the conical end is closely spaced from the outlet end of the nozzle means, preferably a distance of 5-25 mm. The vibrator ymeans are constructed to oscillate at a frequency range of 1.5 to 45K c.p.s.

The fiber loosening apparatus of the present invention will produce proper separation of the fibers without requiring a screening system ahead of the liber loosening apparatus Ias is necessary with existing apparatus of the prior art. This will not only reduce the necessary investment cost of the installation, but this will also reduce losses of -good fibers occurring in a screening system through which stock is passed according to the prio-r art before it is finely pulped.

According to the method of the present invent-ion, the waste paper is subjected first to an extended hydration, causing by means of a swelling effect loosening of hydrated cellulose fibers and loosening glue, coloring matter and inorganic components and fillers surrounding the bers. In this way the bers become suitably prepared for the further treatment consisting in the complete separation from the matter uniting the fibers. In the apparatus for loosening the fibers the thus prepared pulp diluted to the proper density is fed in a concentrated stream under high pressure into a chamber and subjected to mechanical oscillation at high frequency thereby separating the fibers from each other and Iseparating and washing adhesives, coloring matter such as print-ing ink and other matter from the fibers. The fibers thus obtained will have a good felting quality and can be easily screened from the other matter contained in the original waste paper. Fiber losses are avoided in a screening system arranged behind the lfiber loosening apparatus since the fibers in the stock entering the screening system will be completely separated from each other and the stock will not contain agglomeration of unpulped paper.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both las to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read -in connection with the accompanying drawings, in which:

FIG. 1 is a schematic fiow sheet of a plant for processing waste paper for subsequent manufacture of paper or cardboard therefrom;

FIG. 2 is a schematic side View of the fiber loosening apparatus according to the present invention;

FIG. 3 is a top view of the apparatus shown in FIG. 2; and

FIG. 4 is a partial cross sectional view of the apparatus shown in FIGS. 2 and 3 and drawn to an enlarged scale.

Referring now to the drawings and more particularly to FIG. 1 of the same, in which the overall arrangement of apparatus for processing waste paper for subsequent production into paper or cardboard is shown in the form of a schematic flow sheet, it will be seen that such an arrangement preferably comprises a vortex pulper y1 of known construction into which waste paper in the form of bundles or in loose form is fed as indicated by the arrow A together with diluting water, as indicated by the arrow B which preferably includes a certain amount of disinfecting material continuously fed into the stream of diluting water by a dosing apparatus of known construction and not shown in the drawing. The mixture of waste paper and diluting liquid is subjected in the vortex pulper 1 to a rough pulping operation and heavy unpulpable impurities are discharged from the pulper while the thus produced stock is fed into the mixing tank 2 provided with partitions 2 to cause further sedimentation of unpulpable heavy parts which are discharged from the mixing tank while the remaining stock is fed by the pump 3 into a thickening filter 4 where the stock is thickened and subjected to a washing operation. From the thickening filter 4 in which the stock is thickened preferably to a density of 10-22%, the thickened stock is fed by the pump 5 into the top of a storage and hydration tower 6 in which the fibers are subjected to swelling and hydration -to prepare the same in the manner as mentioned above for their subsequent processing. The storage and hydration tower 6 has a height of 8-12 meters so that a considerable amount of densified pulp can be stored therein to be subjected to an extended hydration and swelling preferably for a time of 48 to 76 hours. The densied stock fed into the tower 6 at the top thereof gradually sinks to the bottom of the tower and pressurized water is fed by the pump 7 through a plurality of nozzles 6 in the bottom region of the tower 6 into the stock to dilute the stock in the discharge region to a density of 0.5 to 5%. A plurality of mixing impellers 6", one of which is schematically shown in FIG. 1, may be provided in the bottom region of the tower 6 to properly `mix the diluting water fed through the nozzle 6 into the 'bottom region of the tower with the stock therein. The thus diluted stock is fed by a pump 8 into a mixing tank 9 which may also be provided with partitions similar to the partitions 2 of the mixing tank 2 and heavy unpulpable parts still retained in the stock will settle at the bottom of the mixing tank 9 and so that they can be discharged therefrom while ythe thus further clarified stock is fed by the pump 10 under high pressure in the fiber loosening apparatus 11, schematically shown in FIG. 1, and which will be described in further detail later on. In the fiber loosening apparatus the stock is subjected to oscillations of high frequency to separate the fibers from each other and from the material bonding the fibers to each other in the waste paper. From the fiber loosening apparatus 11 the stock is fed by the pump 12 or by gravity into a screening system 13 from where it is discharged and further processed in the manner as known in the art.

Instead of a single storage and hydration tower as shown in the flow sheet a plurality of such towers may be used, and in this case a proper distribution piping system has to be provided between the pump 5 and the upper inlet ends of the various towers, as well as between the outlet ends of the various towers and the pump 8 so that the towers may be supplied with stock and stock be discharged from the towers in any desired sequence.

FIGS. 2 and 3 illustrate respectively in a side view and in a top view the fiber loosening apparatus 11 and the feed pump 10 connected thereto, which are schematically shown in the flow sheet of FIG. 1.

As can be seen from FIGS. 2 and 3, the stock from the mixing tank 9 is fed by the pump 10, which may be a centrifugal pump of known construction, into distributor head 17 arranged at the outlet end of the pump 10. The centrifugal pump 10` is driven, for instance, by an electromotor 14 over a gear reduction unit 15 mounted with the motor 14 and the pump 10 on a common bed plate 16. The hollow substantially cylindrical distributor head 17 mounted on the outlet end of the pump 10 and communicating ltherewith has in the interior thereof a substantially conical deflector 17a guiding the pulp fed under high pressure by the pump 10 into the distributor head 17 into four pipe nipples 18 projecting upwardly from the cover of the distributor head. The flow of pulp through the nipples 18 is controlled by valves 19 and manometers 20 arranged downstream of the valves are provided for indicating the pressure of the pulp passing through the nipples 18. Pressure hoses 21 respectively connect the outlet ends of the nipples 18 with nozzle means 24 of the fiber loosening apparatus 11.

The fiber loosening apparatus 11 includes a cylinder or chamber means 22 closed at the top and the bottom and mounted on a support frame or casting 31. The cover 23 of the chamber means 22 carries a plurality of nozzle means 24, four nozzle means are shown in the apparatus illustrated, which extend with lower portions thereof through corresponding openings in the cover 23. Each of the nozzle means 24 is provided with a gate valve 25 for a purpose las will be described later on. Coaxially arranged with the outlet end of each nozzle means 24 are vibrator means 26, one of which is schematically shown in FIG. 2.

An outlet conduit 30 communicates with the interior of the chamber means 22 for discharging the pulp after the same has been processed in the chamber means therefrom and the apparatus includes further at the bottom of the chamber 22 an auxiliary discharge opening normally closed by the valve 29 for discharge of sediments settling at the bottom of the chamber into sludge discharge conduit 28.

FIG. 4 shows in section and on an enla-rged scale one of the nozzle means 24 mounted on the cover 23 of the chamber means 22, as well as the vibrator means 26 and the gate valve 25 coordinated with the nozzle means.

FIG. 4 shows one of the openings 23 formed in the cover 23 of the chamber means 22 and an annular member 32, preferably in the form of a casting, Coaxially arranged with the opening 23 and held on the cover 23 in any convenient manner, for instance, by screws not shown in the drawing. A tubular member 33 projects upwardly from the annular member 32 Coaxially arranged therewith and this tubular member 33 has a lower flange 34 and an upper flange 35. The tubular member 33 is fluidtightly held on the annular member 32 by means of screw bolts 34 extending through openings in the lower flange 34 of the tubular member 33 into corresponding threaded bores in the annular member 32. Coaxially arranged with the tubular member 33 and extending with a lower portion thereinto is an outer guide sleeve 36 having at the lower end thereof a radially extending flange 38 of an outer diameter substantially equal to the inner diameter of the tubular member 33 so as to slidably engage the inner surface of the tubular member. The guide sleeve 36 has intermediate its ends a flange 37 abutting against the upper ilange 35 of the tubular member 33 and connected thereto, when the nozzle means is in its operating position as shown in FIG. 4, by three screw bolts and nuts 43, only one of which is shown in FIG. 4. Coaxially arranged within the outer guide sleeve 36 is an inner sleeve 39 having an outer diameter substantially equal to the inner diameter of the guide sleeve 36 so that the inner sleeve is slidably guided in the outer guide sleeve 36. The inner sleeve 39 is preferably counterbored at the lower end thereof and the cylindrical wall of the counterbore is formed with a screw thread engaging with a corresponding screw thread on the outer cylindrical surface of a nozzle part 39' arranged in the counterbore of the inner sleeve 39. The nozzle part 39 is formed with a conical bore therethrough gradually tapering from the inner diameter of the inner sleeve 39 toward the outlet end of the nozzle part 39. Coaxially arranged with the outer guide sleeve 36 is another tubular member 44 having an inner diameter substantially equal to that of the outer guide sleeve 36. A ilange 45 at the upper end of the inner tubular member 44 abuts against the lower flange 38 of the guide sleeve 36 and is connected thereto by screw bolts 46. The flange 45 has an outer diameter substantially equal to that of the flange 38 so that the flange 4S is likewise slidably guided in the outer tubular member 33.

Vibrator means are arranged coaxially with the nozzle means 24 below the outlet end of the nozzle member 39 in the inner tubular member 44. The vibrator means include a vibrator body 47 of substantially cylindrical shape and having a conical upper end 48 tapering toward the outlet end of the nozzle member 39'. The vertex angle of the conical end 48 is-preferably between 60 and 120. The lower end of the vibrator body 47 may also be tapered as shown in FIG. 4. The vibrator body 47 is carried by means of four set screws 49 extending through threaded bores in the inner tubular member 44 and engaging with the pointed ends thereof into corresponding cavities of the body 47. The set screws 49 are arranged to support the elongated vibrator body 47 at nodal points of its elastic vibration.

The vibration of the vibrator body may be obtained by the stream of pulp under high pressure leaving the outlet end of the nozzle and being divided by the vibrator body 47, or the vibration may also be electrically produced, for instance, the vibrator body may be in the form of a magneto-strictive oscillator, well known in the art, in which case the body 47 is provided with a winding 47' connected to a source of high frequency current. In either case the vibrator body is constructed to vibrate at a frequency in the range of 1.5 to 45K c.p.s. The tubular member 44 is formed in its cylindrical wall with large openings 44 therethrough so that the vibrations produced may expand laterally beyond the member 44. The tapered end 48 of the vibrator body 47 is spaced a small distance, that is, 5 to 25 mm., from the outlet end of the nozzle part 39.

To change the distance between the free end of the conical portion 48 of the vibrator body 47 from the outlet end of the nozzle part 39', a rotary cap nut 40 is mounted in the region of the upper end of the inner sleeve 39 of the nozzle means 24 coaxially therewith and held against axial displacement with respect to the inner sleeve 39 between a shoulder on the sleeve and a snap ring 41, while being rotatable about the axis of the inner sleeve 39. The nut 40 is provided with an inner screw thread cooperating with an outer screw thread on the upper end of the outer guide sleeve 36 so that by turning the nut 40 about its axis, the relative axial position of the inner sleeve 39 relative to the guide sleeve 36 may be changed and therewithrthe spacing between the outlet end of the nozzle part 39' and the tapered end 48 on the vibrator body 47. The upper end of the inner sleeve 39 is provided with an outer screw thread cooperating with an inner screw thread of a tting on the end ofl the respective pressure hose 21 for connecting the respective pressure hose to the respective nozzle means.

The nozzle means 24 together with the vibrator means 26 carried thereby may be raised from the working position shown in lFIG. 4 to a cleaning position in which the lower flange 38 of the guide sleeve is substantially flush with the top rim of the outer tubular member 33. To guide the nozzle means 24 during the outward movement thereof, three guide pins 50, only one of which is shown in FIG. 4, are provided projecting angularly displaced through angles of 120 from each other upwardly from the flange 35 and extending through corresponding bores in the ilange 37 of the outer guide sleeve 36. A nut 51 may be provided at the upper end of one of the guide pins 50 to limit the upward movement of the nozzle means 24. When the nozzle means is raised to the cleaning position, the cap nut 40 may be unscrewed and the inner sleeve 39 with the nozzle part 39 may be subsequently removed from the guide sleeve for proper cleaning of the inner sleeve and the nozzle.

In order to carry out such a cleaning operation of one nozzle while operating the ber loosening apparatus 11 with the remaining nozzles, a gate valve 25 is provided for each of the nozzle means 24. The gate valve 25' may include a blade 52 guided in an appropriate slot 52 of the annular member 32. The outer end of the blade 52 extending, as viewed in FIG. 4, to the left of the annular member 32 is ixedly connected, for instance, by rivets, to the forked end of a threaded spindle 53 cooperating with a nut 5S to which a hand wheel 54 is keyed for turning the nut 55 about its axis. The nut 55 is held against axial displacement by the member 57 connected to the left end, as viewed in FIG. 4, of the annular member 32 by studs 58 as well as by the counternut 56 engaging the left end of the hub of the hand wheel 54.

When the nozzle means 24 and the vibrator means 26 Carried thereby are shifted to their cleaning position in which the ange 37 will engage the stop nut 51 on the guide pin 50, the lower end of the vibrator body 47 will be slightly above the groove 52 so that the gate valve may be closed preventing thereby any splashing of pulp through the respective opening 23' in the cover 23 during cleaning of the nozzles arranged at this opening.

The ber loosening apparatus 11 above described will operate as follows:

Pulp of a density of 0.5 to 5% from the mixing tank 9 is fed by the centrifugal pump 10 through lthe distributor head 17 and the plurality of pressure hoses 21 at high pressure, in the order of to 230` and preferably at a pressure of about 210 lbs. per square inch into the respective nozzle means 24 so that in each of the nozzle means a concentrated stream of pulp under high pressure and high speed leaving the outlet end of the nozzle part 39 will impinge onto the conical end 48 of the vibrator body 47 and the latter vibrating at a frequency of 1.5 to 45K c.p.s. will thereby subject the stream to mechanical vibrations of high frequency. The mechanical vibrations thus produced will expand from the vibratory Ibody 47 into the surrounding stock in the chamber means 22 to cause a perfect separation of the iibers in the stock from each other and the separa-tion of the bers from any binding and similar material holding the fibers together. The separation of the fibers from substances which bind the same together is obtained by the abrupt change of the pressure at the nozzle outlet and the simultaneous effect of mechanical vibrations in the chamber 22. This separation will occur without breaking of the fibers in small fragments. The nal pulp stock is discharged from the chamber means 22 through the conduit 30 while impurities and sludge will settle at the bottom of the chamber means from which they are intermittently discharged through the valve 29 into the sludge discharge conduit 28.

Waste paper and even cardboard of practically any kind can be processed with the method and apparatus of the present invention with the exception of parained papers, bituminous papers or other heavily coated or impregnated papers.

It will be understood that each of the elements described above, or two or more together, may also iind a useful application in other types of apparatus for loosening fibers diiering from the types described above.

While the invention has been illustrated and described as embodied in an apparatus for loosening fibers of Waste paper pulp, it is not intended to be limited to the details shown, since various modications and structural changes may be made Without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully rea' veal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specified aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. A method of loosening fibers of waste paper comprising the steps of mixing waste paper and water and subjecting the mixture to a coarse pulping operation; thickening the pulp thus obtained; feeding the thickened pulp into a storage tank and subjecting it therein to swelling and hydration; discharging said pulp from said tank while diluting it to a smaller density; subjecting a stream of the diluted pulp to mechanical vibrations of high frequency for loosening the fibers; and finally screening said pulp.

2. A method of loosening fibers of waste paper comprising the steps of mixing Waste paper and water and subjecting the mixture to a coarse pulpng operation; thickening the pulp thus obtained to a density of itl-22%; feeding the thickened pulp into a storage tank and subjecting it therein to swelling and hydration; discharging said pulp from said tank while diluting it to a density of 0.5-%; subjecting a stream of the diluted pulpto mechanical vibrations in longitudinal direction of the stream and at a frequency range of 1.5-45K c.p.s. for loosening the fibers; and finally screening said pulp.

3. A method of loosening fibers of waste paper comprising the steps of mixing waste paper and water and subjecting the mixture to a coarse pulping operation; thickening the pulp thus obtained; feeding the thickened pulp into a storage tank and subjecting it therein to swelling and hydration; discharging said pulp from said tank while diluting it to a smaller density; feeding the diluted pulp under pressure in a concentrated stream in one direction; subjecting said stream to mechanical vibrations longitudinal said one direction at a frequency range of 1.5-45K c.p.s. for loosening the fibers; and finally screening said pulp.

4. In an apparatus for loosening fibers of waste paper pulp, in combination, chamber means; nozzle means having an outlet end communicating with the interior of said chamber means for directing a pressurized stream of pulp into said chamber means; and vibrator means axially aligned `with said nozzle means adjacent said outlet end and vibrating in longitudinal direction of said stream and at high frequency for subjecting said stream to mechanical vibrations.

5. In an apparatus for loosening fibers of waste paper pulp, in combination, chamber means; nozzle means having an outlet end communicating with the interior of said chamber means for directing a pressurized stream of pulp intosaid chamber means; and vibrator means axially aligned with said nozzle means adjacent said outlet end and vibrating at high frequency for subjecting said stream to mechanical vibrations, said vibrator means vibrating longitudinal in the direction of said stream at a frequency range of 1.5-45K c.p.s.

6. In an apparatus for loosening fibers of Waste paper pulp, in combination, chamber means; nozzle means having an outlet end communicating with the interior of said chamber means for directing a pressurized stream of pulp into said chamber means; and vibrator means axially aligned with said nozzle means adjacent said outlet end and vibrating at high frequency in axial direction for subjecting said stream to mechanical vibrations in longitudinal direction of said stream, said vibrator means including a vibrator body axially aligned with said outlet end of said nozzle means and having a tapered end facing said outlet end of said nozzle means.

7. In an apparatus for loosening fibers of waste paper pulp, in combination, chamber means; nozzle means having an outlet end communicating with the interior of said chamber means for directing a pressurized stream of pulp into said chamber means; and vibrator means axially aligned with said nozzle means adjacent said outlet end and vibrating in axial direction at high frequency for subjecting said stream to mechanical vibrations in longitudinal direction of said stream, said vibrator means including a substantially cylindrical vibrator body axially aligned with said outlet end of said nozzle means and having a conical end tapering toward said outlet end of said nozzle means.

8. In an apparatus for loosening fibers of waste paper pulp, in combination, chamber means; nozzle means having an outlet end communicating with the interior of said chamber means for directing a pressurized stream of pulp into said chamber means; and vibrator means axially aligned with said nozzle means adjacent said outlet end and vibrating in axial direction at high frequency for subjecting said stream to mechanical vibrations in longitudinal direction of said stream, said vibrator means including a substantially cylindrical vibrator body axially aligned with said outlet end of said nozzle means and having a conical end of a vertex angle of 60-l20 tapering toward said outlet end of said nozzle means and being spaced from said outlet end of said nozzle means a distance of 5-25 mm.

9. In an apparatus for loosening fibers of waste paper pulp, in combination, chamber means having a cover formed with at least one opening therethrough; nozzle means extending through said opening in said cover for directing a pressurized stream of pulp into said chamber means, said nozzle means having an outlet end', vibrator means `axially aligned with said nozzle means adjacent said outlet end and vibrating in axial direction at high frequency for subjecting said stream to mechanical vibrations in longitudinal direction of said stream; and support means on said cover and mounting said nozzle means and said vibrator means movable between a working position in which said outlet end of said nozzle means and said vibrator means are located in said chamber means, and a withdrawn position in which said nozzle means and said vibrator means are withdrawn through said opening in said cover to the outside of said chamber means.

10. In an apparatus for loosening fibers of waste paper pulp, in combination, chamber means having a cover formed with at least one opening therethrough; nozzle means extending through said opening in said cover for directing a pressurized stream of pulp into said chamber means, said nozzle means having an outlet end; vibrator means axially aligned with said nozzle means adjacent said outlet end and vibrating in axial direction at high frequency for subjecting said stream to mechanical vibrations in longitudinal direction of said stream; support means on said cover and mounting said nozzle means and said vibrator means movable between la working position in which said outlet end of said nozzle means and said vibrator means are located in said chamber means, and a withdrawn position in which said nozzle means and said vibrator means are Withdrawn through said opening in said cover to the outside of said chamber means; and gate means for closing said opening in said cover when said nozzle and vibrator means are in said withdrawn position.

11. In an apparatus for loosening fibers of waste paper pulp, in combination, chamber means having a cover formed with at least one opening therethrough; nozzle means extending through said opening in said cover for directing a pressurized stream of pulp into said chamber means, said nozzle means including an outer guide sleeve and an inner sleeve slidably guided in axial direction in said outer guide sleeve and having a converging outlet end, and means for axially shifting said inner sleeve relative to said guide sleeve for adjusting the axial position of said outlet end; vibrator means connected to said guide sleeve to be carried thereby axially aligned with said nozzle means adjacent s-aid outlet end and vibrating in axial direction at high frequency for subjecting said stream to mechanical vibrations yin longitudinal direction of said stream; support means on said cover and connected to said guide sleeve for mounting said nozzle means and said vibrator means movable between a working position in which said outlet end of said nozzle means and said vibrator means are located in said chamber means, and a withdrawn position in which said nozzle means and said vibrator means are withdrawn through said opening in said cover to the outside of said chamber means; `and gate means for closing said opening in said cover when said nozzle and vibrator means are in said withdrawn position.

12. In an apparatus for loosening bers of waste paper pulp, in combination, chamber means; nozzle means having an outlet end for directing a pressurized stream of pulp into said chamber means; and an elongated vibrator body 10 axially aligned with said nozzle means and having a pointed end directed toward `and being spaced a short distance from said outlet end of said nozzle means, said vibrator body being constructed and mounted to be vibrated at high frequency in lthe direction of its elongation by the pressurized stream of pulp impinging on said pointed end, whereby said stream of pulp is subjected by said vibrator body to high frequency mechanical vibrations.

References Cited UNITED sTATEs PATENTS 2,363,937 11/1944 Brandt et al 241--5 X 3,039,703 6/ 1962 Cohn et al. 241--5 3,058,674 10/ 1962 Kocher 241-5 X ANDREW R. JUHASZ, Primary Exam-incr. 

1. A METHOD OF LOOSENING FIBERS OF WASTE PAPER COMPRISING THE STEPS OF MIXING WASTE PAPER AND WATER AND SUBJECTING THE MIXTURE TO A COARSE PULPING OPERATION; THICKENING THE PULP THUS OBTAINED; FEEDING THE THICKENED PULP INTO A STORAGE TANK AND SUBJECTING IT THEREIN TO SWELLING AND HYDRATION; DISCHARGING SAID PULP FROM SAID TANK WHILE DILUTING IT TO A SMALLER DENSITY; SUBJECTING A STREAM OF THE DILUTED PULP TO MECHANICAL VIBRATIONS OF HIGH FREQUENCY FOR LOOSENING THE FIBERS; AND FINALLY SCREENING SAID PULP. 